Three-dimensional photonic crystal and process for production thereof as well as probe used therefor

ABSTRACT

The present invention provides a practically effective three-dimensional photonic crystal, and a process for the production thereof as well as a probe used therefor wherein a three-dimensional photonic crystal comprises a plurality of two-dimensional photonic crystal plates each provided with through holes and different types of two-dimensional photonic crystals; a plurality of positioning members to be located in the above-described through holes in the plurality of the two-dimensional photonic crystal plates; and the above-described positioning members being located in the through holes in the two-dimensional photonic crystal plates adjacent to each other among the pluralities of two-dimensional photonic crystal plates to be laminated in such that the pluralities of the two-dimensional photonic crystal plates obtain a periodic structure in response to wavelengths of light.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a three-dimensional photoniccrystal and a process for the production thereof as well as a probe usedtherefor, and more particularly to a three-dimensional photonic crystalinto which an optical phase shift region (defect region) can be insertedarbitrarily, so that which is used suitably in case of constitutingsemiconductor lasers, optical waveguides and the like, and a process forthe production thereof as well as a probe used therefor.

[0003] 2. Description of the Related Art

[0004] Heretofore, a photonic crystal having a similarity as that ofsolid crystal and involving an artificial periodic structure has beenknown. More specifically, photonic crystal is the one having a two- or athree-dimensionally periodic structure wherein two or more types ofdielectrics, semiconductors, metals and air are alternately disposed ina repeated manner with a period corresponding to around opticalwavelengths.

[0005] In the present specification, it is to be noted that photoniccrystal having a two-dimensionally periodic structure is referred to as“two-dimensional photonic crystal”, while photonic crystal having athree-dimensionally periodic structure is referred to as“three-dimensional photonic crystal”.

[0006] In solid crystal, atoms are disposed periodically wherein a waveof electron exhibits a certain particular behavior while capturing aperiodicity of the crystal. Likewise, in a periodic structure ofphotonic crystal, not a wave of electrons, but a wave of light exhibitsa certain particular behavior, which is determined by energy dispersioncharacteristics and referred to as photonic band. Furthermore, inphotonic crystal, it is possible to produce a forbidden gap whereinexistence of light can be forbidden, which is referred to as “photonicbandgap”.

[0007] From the facts as described above, it is assumed that there is ahigh possibility being capable of freely controlling light by an opticaldevice constituted from three-dimensional photonic crystals, as in thecase where a semiconductor device can control freely electrons.

[0008] For this reason, a manner for producing three-dimensionalphotonic crystals has been proposed heretofore as a prerequisite forfabricating an optical device constituted by three-dimensional photoniccrystals, for example, three-dimensional etching method, wafer fusionlaminating method, automatic cloning method or the like method is knownin this respect.

[0009] Three-dimensional etching method means a method wherein asubstrate is etched at various angles to produce three-dimensionalphotonic crystals involving three-dimensional structures. Furthermore,wafer fusion laminating method is the one wherein a plurality ofsemiconductors formed into striped shapes are accurately positioned tolaminate with each other by the use of a laser beam diffraction pattern,whereby three-dimensional photonic crystals involving three-dimensionalstructures are produced. Moreover, automatic cloning method is the onewherein an irregular surface has been previously formed on a substrate,and crystals are grown on the irregular surface retaining the surfacemorphology, whereby three-dimensional photonic crystals havingthree-dimensional structures are prepared.

[0010] However, any of the above-described conventional methods is notsufficient for producing three-dimensional photonic crystals applicableto optical devices, so that a proposition for a practically effectiveand novel method has been strongly demanded.

OBJECT AND SUMMARY OF THE INVENTION

[0011] The present invention has been made in view of theabove-described needs.

[0012] Accordingly, an object of the invention is to provide apractically effective three-dimensional photonic crystal and a processfor the production thereof as well as a probe used therefor.

[0013] In order to achieve the above-described object, athree-dimensional photonic crystal, a process for the production thereofas well as a probe used therefor according to the present invention arearranged in such that a three-dimensional photonic crystal having astereoscopic structure is intended to fabricate by positioning aplurality of plates in which two-dimensional photonic crystals have beenformed, so that these plates are laminated with each other.

[0014] Namely, a three-dimensional photonic crystal according to thepresent invention comprises a plurality of two-dimensional photoniccrystal plates each provided with different types of two-dimensionalphotonic crystals; and the pluralities of two-dimensional photoniccrystal plates being positioned respectively to be laminated so as toobtain a periodic structure in response to wavelengths of light.

[0015] Furthermore, a three-dimensional photonic crystal according tothe present invention comprises a plurality of two-dimensional photoniccrystal plates each provided with through holes and different types oftwo-dimensional photonic crystals; a plurality of positioning members tobe located in the above-described through holes in the plurality of thetwo-dimensional photonic crystal plates; and the above-describedpositioning members being located in the through holes in thetwo-dimensional photonic crystal plates adjacent to each other among thepluralities of two-dimensional photonic crystal plates to be laminatedin such that the pluralities of the two-dimensional photonic crystalplates obtain an accurate periodic structure in response to wavelengthsof light.

[0016] Moreover, a three-dimensional photonic crystal according to thepresent invention comprises a flat plate-like first two-dimensionalphotonic crystal plate provided with first through holes on a firstframe as well as with first two-dimensional photonic crystals in aregion inside the first frame; a flat plate-like second two-dimensionalphotonic crystal plate provided with second through holes, beingpositioned with respect to the above-described first through holes, on asecond frame as well as with a second two-dimensional photonic crystalin a region inside the second frame; positioning members located in suchthat the first through holes being communicated with the second throughholes; and the above-described positioning members being located in suchthat the through holes in the first two-dimensional photonic crystalplate being communicated with the through holes in the secondtwo-dimensional photonic crystal plate to be positioned, whereby thefirst two-dimensional photonic crystal plate is laminated with thesecond two-dimensional photonic crystal plate so as to obtain anaccurate periodic structure in response to wavelengths of light.

[0017] Further, a three-dimensional photonic crystal according to thepresent invention may be modified in such that the above-described firstthrough holes and the above-described second through holes are circularholes, respectively, a radius in each of the circular holes issubstantially equal to thicknesses of the first two-dimensional photoniccrystal plate and the second two-dimensional photonic crystal plate, andeach of the above-described positioning members is a sphere having adiameter corresponding to substantially doubled radius of the circularhole.

[0018] Still further, a process for the production of athree-dimensional photonic crystal according to the present inventioncomprises the steps of allowing pluralities of two-dimensional photoniccrystal plates each provided with different types of two-dimensionalphotonic crystals to adhere or to be held onto the extreme end of aprobe in accordance with micromanipulation thereby moving them,respectively; and positioning the pluralities of two-dimensionalphotonic crystal plates with each other by means of moving them whereinthese two-dimensional photonic crystal plates have been allowed toadhere or to be held onto the extreme end of the probe, so that thepluralities of two-dimensional photonic crystal plates are laminated soas to obtain an accurate periodic structure in response to wavelengthsof light.

[0019] Yet further, a process for the production of a three-dimensionalphotonic crystal according to the present invention may be modified insuch that the above-described two-dimensional photonic crystal platesare allowed to adhere or to be held onto the extreme end of the probe bymeans of electrostatic adhesive force wherein a predetermined voltage isapplied to the probe.

[0020] Besides, a process for the production of a three-dimensionalphotonic crystal according to the present invention may be modified insuch that the above-described two-dimensional photonic crystal platesare connected to outer hull regions with bridges held in midair; andapplying a load to the bridges with the probe to break down them therebyallowing the two-dimensional photonic crystal plates to adhere on theextreme end of the probe to move them as a result of such break-down ofthe bridges.

[0021] In addition, a process for the production of a three-dimensionalphotonic crystal according to the present invention may be modified insuch that the above-described respective positioning of the pluralitiesof two-dimensional photonic crystal plates is conducted by moving eachof the pluralities of two-dimensional photonic crystal plates with theprobe, and each of the pluralities of two-dimensional photonic crystalplates is allowed to abut against a structural body having apredetermined shape.

[0022] Furthermore, a process for the production of a three-dimensionalphotonic crystal according to the present invention may be modified insuch that each of the above-described pluralities of two-dimensionalphotonic crystal plates is a flat plate-like body wherein through holeshave been defined on its frame part, besides a region inside the framepart is provided with different types of two-dimensional photoniccrystals from one another; and positioning members are located in thethrough holes in two-dimensional photonic crystal plates adjacent toeach other among the pluralities of two-dimensional crystal plates toposition them, whereby the pluralities of two-dimensional photoniccrystal plates are laminated so as to obtain a periodic structure inresponse to wavelengths of light.

[0023] Moreover, a process for the production of a three-dimensionalphotonic crystal according to the present invention may be modified insuch that each of the above-described through holes is a circular hole;a radius of the circular hole is substantially equal to each thicknessof the pluralities of two-dimensional photonic crystal plates; and eachof the above-described positioning members is a sphere a diameter ofwhich is equal to a substantially doubled radius of the circular hole.

[0024] Further, a process for the production of a three-dimensionalphotonic crystal according to the present invention may be modified insuch that a micro- and/or submicro-meter sized part for constituting anoptical phase controlling region is inserted by means of theabove-described probe in the case when the pluralities oftwo-dimensional photonic crystal plates are laminated so as to obtain aperiodic structure in response to wavelengths of light.

[0025] Still further, a probe according to the present inventioncomprises an inner core made of a metal; an insulating layer formedaround the inner core; an outer metallic film formed on the outerperiphery of the insulating layer except for the extreme end portionthereof; the extreme end portion of the insulating layer having a shapeof a flat surface; and an electric field being generated in the vicinityof marginal portion of the extreme end portion by applying a voltageacross the inner core and the outer metallic film, so that a material iselectrostatically sticked.

[0026] Yet further, a probe according to the present invention comprisesan insulator needle with the extreme end portion of which is a flattenedsurface; a first electrode and a second electrode disposed on theinsulator needle so as to constitute a comb electrode in theabove-described flattened surface of the extreme end portion in theinsulator needle; an insulating film covering the above-describedinsulator needle provided with the first electrode and the secondelectrode; a metallic shield formed on the outer periphery of theinsulating film except for a side of the extreme end portion, which isthe flattened surface of the insulator needle; and an electric fieldbeing generated over the flattened surface in the extreme end portion ofthe insulator needle by applying different voltages with respect to themetallic shield from one another to the first electrode and the secondelectrode, respectively, so that a material is electrostatically stickedto the extreme end portion of a probe.

[0027] Therefore, a practically effective three-dimensional photoniccrystal, and a process for the production thereof as well as a probeused therefor can be provided in accordance with the above-describedpresent invention.

[0028] In other words, it is possible to implement accurate laminationof two-dimensional photonic crystal plates, even if patterns oftwo-dimensional photonic crystal become how much complicated.

[0029] Besides, since two-dimensional photonic crystal plates or partssuch as positioning members, which extend from a submicron to a micronorder, can be freely assembled with each other, light-emitting materialsor materials having different refractive indices can be introduced intoa dot-like or an arbitrary region as a light control region (defectregion). Accordingly, a manner capable of fabricating freely suchthree-dimensional structure as described above is an indispensabletechnique for making photonic crystals to become optical devices.

BRIEF DESCRIPTION OF THE DRAWING

[0030] The present invention will become more fully understood from thedetailed description given hereinafter and the accompanying drawingswhich are given by way of illustration only, and thus are not limitativeof the present invention, and wherein:

[0031] FIGS. 1(a) and 1(b) are views each showing a three-dimensionalphotonic crystal according to an example of a preferred embodiment ofthe present invention wherein FIG. 1(a) is a front perspective view, andFIG. 1(b) is an exploded perspective view of FIG. 1(a);

[0032] FIGS. 2(a), 2(b), and 2(c) are explanatory views each showing amanner for fabricating an air bridge type two-dimensional photoniccrystal plate;

[0033]FIG. 3 is a graphical representation indicating a relationshipbetween the standerized frequency and the ratio of widths and periods ofa block to have a photonic band gap formed in the case where a wood pilestructure is formed by using InP as a material;

[0034]FIG. 4 shows electron micrographs of two-dimensional photoniccrystal plates;

[0035] FIGS. 5(a) and 5(b) are explanatory views each showing a mannerfor constituting a three-dimensional photonic crystal by positioning thepositioning members into the through holes;

[0036] FIGS. 6(a) and 6(b) are explanatory views each showing a mannerfor constituting a three-dimensional photonic crystal by laminatingtwo-dimensional photonic crystal plates;

[0037] FIGS. 7(a) and 7(b) are explanatory views each showing a mannerfor constituting a three-dimensional photonic crystal by laminatingtwo-dimensional photonic crystal plates;

[0038] FIGS. 8(a) and 8(b) are electron micrographs wherein FIG. 8(a) isthe one showing a state in which positioning members are positioned intoholes of a first layer, and FIG. 8(b) is an enlarged one showing a partenclosed by a white rectangle in FIG. 8(a);

[0039] FIGS. 9(a) and 9(b) are electron micrographs wherein FIG. 9(a) isthe one showing a state in which two layers of two-dimensional photoniccrystal plates are laminated, and FIG. 9(b) is an enlarged one of a partenclosed by a white rectangle in FIG. 9(a);

[0040] FIGS. 10(a) and 10(b) are electron micrographs wherein FIG. 10(a)is the one showing a state in which three layers of two-dimensionalphotonic crystal plates are laminated, and FIG. 10(b) is an enlarged oneof a part enclosed by a white rectangle in FIG. 10(a);

[0041]FIG. 11 is an electron micrograph showing a state wherein bridgesare pushed with a probe to cut off a two-dimensional photonic crystalplate from an outer hull region of a substrate;

[0042]FIG. 12 is an electron micrograph showing a state wherein atwo-dimensional photonic crystal, which has been cut off and sticked ona probe, is brought on another two-dimensional photonic crystal whereinpositioning microspheres have been inserted into through holes;

[0043]FIG. 13 is an electron micrograph showing a state wherein twopieces of two-dimensional photonic crystal plates are superposedsubstantially completely one another;

[0044]FIG. 14 is a graphical representation indicating spectra in thecase when reflected waves are measured in each increase of one layer ofa two-dimensional photonic crystal plate wherein one layer (¼ period),three layers (¾ period), and four layers (one period) are laminated oneanother, respectively;

[0045] FIGS. 15(a), 15(b), and 15(c) are explanatory views each showinga probe according to another preferred embodiment;

[0046] FIGS. 16(a) and 16(b) are explanatory views each showing a probeaccording to a further preferred embodiment;

[0047]FIG. 17(a) is a perspective explanatory view showing a case wherepositioning is made by using a part of each two-dimensional photoniccrystal patterns, while 17(b) is a perspective explanatory view showinga case where positioning is made by using a through hole defined on eachof two-dimensional photonic crystal patterns;

[0048] FIGS. 18(a), 18(b), 18(c), and 18(d) are explanatory views eachshowing another positioning method for two-dimensional photonic crystalplates; and

[0049] FIGS. 19(a) and 19(b) are explanatory views each showing afurther positioning method for two-dimensional photonic crystal plates.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0050] In the following, an example of a preferred embodiment of athree-dimensional photonic crystal and a process for the productionthereof as well as a probe used therefor according to the presentinvention will be described in detail by referring to the accompanyingdrawings.

[0051] FIGS. 1(a) and 1(b) are views each showing a three-dimensionalphotonic crystal according to an example of a preferred embodiment ofthe present invention wherein FIG. 1(a) is a front perspective view, andFIG. 1(b) is an exploded perspective view of FIG. 1(a).

[0052] Namely, a three-dimensional photonic crystal 10 is prepared bylaminating alternately a flat plate-like two-dimensional photoniccrystal plate 14 a involving a two-dimensional photonic crystal 12 awith a flat plate-like two-dimensional photonic crystal plate 14 b, atype of which is different from that of the two-dimensional photoniccrystal plate 14 a, involving a two-dimensional photonic crystal 12 b ina period of around wavelengths of light.

[0053] In the two-dimensional photonic crystal plate 14 a (or 14 b), thetwo-dimensional photonic crystal 12 a (or 12 b) is prepared by repeatingalternately two or more types of dielectrics, semiconductors, metals,air and the like with a period of around wavelengths of light in aregion inside a frame 16 a (or 16 b). In the present embodiment, thetwo-dimensional photonic crystal 12 a formed in a region inside theframe 16 a has involved the same pattern as that of the two-dimensionalphotonic crystal 12 b formed in a region inside the frame 16 b. In thisrespect, when these two-dimensional photonic crystals each having thesame pattern are rotated at 90° with each other to laminate them, twotypes of two-dimensional photonic crystals are laminated.

[0054] With respect to the two-dimensional photonic crystal plate 14 aand the two-dimensional photonic crystal plate 14 b, the two-dimensionalphotonic crystal 12 a and the two-dimensional photonic crystal 12 b aswell as a region of the frame 16 a and a region of the frame 16 b aredimensioned so as to coincide with each other, when they are superposedone another as shown in FIG. 1(a). It is to be noted that a size of thetwo-dimensional photonic crystal 12 a must coincide with that of thetwo-dimensional photonic crystal 12 b, when both of the two-dimensionalphotonic crystals 12 a and 12 b are superposed one another (in otherwords, a region defined by the inside of the frame 16 a must coincidewith that defined by the inside of the frame 16 b, when both of theframes 16 a and 16 b are superposed one another), but it is notnecessarily required to coincide an outer region of the frame 16 a withthat of the frame 16 b, when both the frames 16 a and 16 b aresuperposed one another.

[0055] In the present embodiment, although outer regions of thetwo-dimensional photonic crystals 12 a and 12 b (in other words, insideregions of the frames 16 a and 16 b) as well as outer regions of theframes 16 a and 16 b are shaped in squares, respectively, the inventionis not limited to such square shapes as a matter of course.

[0056] Each thickness t of the two-dimensional photonic crystal plates14 a and 14 b is, for example, from around 3 nm to 1 mm. Furthermore, aside L of the square two-dimensional photonic crystal plate 14 a ortwo-dimensional photonic crystal plate 14 b is, for example, from around10 nm to 10 mm, so that a square measure “L×L” of the two-dimensionalphotonic crystal plate 14 a or the two-dimensional photonic crystalplate 14 b is, for example, from around “10 nm×10 nm=100 nm²” to “10mm×10 mm=100 mm²”.

[0057] A plurality of circular through holes 18 is defined on properpositions in the frames 16 a and 16 b, respectively. Dimensions andalignments of the plurality of through holes defined on these frames 16a and 16 b are arranged in such that at least parts of them coincide tocommunicate with each other in the case when the two-dimensionalphotonic crystal plate 14 a is superposed on the two-dimensionalphotonic crystal plate 14 b. Moreover, a radius r of the through hole 18(i.e., a diameter of the through hole 18 is 2r.) is dimensioned tocorrespond to the thickness t of the two-dimensional photonic crystalplate 14 a or the two-dimensional photonic crystal plate 14 b with eachother.

[0058] In the three-dimensional photonic crystal 10, a microsphere 20being a spherical body having a diameter 2r corresponding to thediameter 2r of the through hole 18 is used for a positioning member,which is inserted into the through holes 18 and 18 in the adjacenttwo-dimensional photonic crystal plates 14 a and 14 b, respectively, toposition these photonic crystal plates 14 a and 14 b, when they arelaminated. As a result, the two-dimensional photonic crystal plate 14 aand the two-dimensional photonic crystal plate 14 b are laminated at anadequate position.

[0059] The three-dimensional photonic crystal 10 having theabove-described constitution is fabricated by superposing thetwo-dimensional photonic crystal plate 14 a and the two-dimensionalphotonic crystal plate 14 b. In this case, the superposition is made bythe use of a probe in accordance with a micromanipulation method.

[0060] More specifically, first, the microsphere 20 is fitted into thethrough hole 18 of the two-dimensional photonic crystal plate 14 a (orthe two-dimensional photonic crystal plate 14 b) to locate themicrosphere 20 therein by the use of a probe in accordance with amicromanipulation method.

[0061] In this case, the probe includes a needle with an extreme end ofwhich has a diameter of from a submicron to a micron order, the oneinvolving an electrode structure therein for electrostatic adhesion, andthe one having a minute handling mechanism such as forceps or the likeat the extreme end thereof.

[0062] In the case where the microsphere 20 is fitted into the throughhole 18 of the two-dimensional photonic crystal plate 14 a (or thetwo-dimensional photonic crystal plate 14 b), a half of the microsphere20 protrudes from a surface of the two-dimensional photonic crystalplate 14 a (or the two-dimensional photonic crystal plate 14 b).

[0063] Then, a pattern of the two-dimensional photonic crystal 12 a (orthe two-dimensional photonic crystal 12 b), which has been rotated at90° with respect to the pattern of the neighboring 2D photonic crystaland half-pitch shifted from the next-neighboring 2D photonic platewherein the microspheres 20 have been fitted into the through holes 18,is prepared. Another through hole 18 in the former two-dimensionalphotonic crystal plate 14 b (or the two-dimensional photonic crystalplate 14 a) is mounted on each half of the microspheres 20 protrudedfrom the surface of the latter two-dimensional photonic crystal plate 14a (or the two-dimensional photonic crystal plate 14 b) to position thesephotonic crystal plates, whereby the two-dimensional photonic crystalplate 14 a and the two-dimensional photonic crystal plate 14 b arelaminated one another. Two-dimentional photonic plates 14 a, 14 b aresequentially laminated by repeating above-mentioned procedure.

[0064] As a result of repeating the above-described operations, athree-dimensional photonic crystal 10 having a three-dimensionallyperiodic structure can be produced.

[0065] In the following, a process for the production of thethree-dimensional photonic crystal 10 will be described in detail byreferring to examples.

[0066] (1) Crystal Growth

[0067] First, a manner for preparing a two-dimensional photonic crystalplate 14 a and a two-dimensional photonic crystal plate 14 b will bedescribed by referring to FIGS. 2(a), 2(b), and 2(c). Thetwo-dimensional photonic crystal plate 14 a and the two-dimensionalphotonic crystal plate 14 b are prepared by growing crystal layers on apredetermined substrate.

[0068] In the present example, the following condition was used.

[0069] Substrate InP (direction of crystal plane) ±0.5 degree

[0070] Indium Source Trimethylindium (TMI:In(CH₃)₃)

[0071] Gallium Source Triethylgallium (TEG:Ga(CH₂CH₃)₃)

[0072] Phosphorous Source Phosphine (PF₃)

[0073] Arsenic Source Arsine (AsH₃)

[0074] Growth Temperature 640 degrees celsius to 680 degrees celsius

[0075] As a manner for growing crystals, MOVCD (Metal-Organic ChemicalVapor Deposition) method was used. TMI is a solid at room temperatures,while TEG is a liquid at room temperatures. Accordingly, hermeticallysealed containers each containing either of these compounds weredisposed in a temperature controlled bath at a temperature of from 20degrees celsius to 30 degrees celsius, hydrogen was fed to the inside ofthe containers to saturate the TMI and the TEG with hydrogen,respectively, and the resulting products were supplied to a reactor. Onan InP substrate, 1 μm to 3 μm of indium-gallium-arsenide (InGaAs) wasgrown, and 0.5 μm to 2 μm of indium-phosphide (InP) was further grownthereon (see FIG. 2(a)).

[0076] (2) Fabrication of Mask

[0077] In order to use as a mask in the following dry etching, 20 nm oftitanium was deposited on the substrate, which was fabricated inaccordance with the above-described manner of “(1) Crystal Growth”, bymeans of vapor deposition, and 400 nm to 1 μm of nickel were depositedon the resulting titanium.

[0078] (3) Drawing

[0079] A resist “ZEP520-22” (trademark) was used for electron-beamlithography. Five hundred (500) nm thickness of the “ZEP520-22” (trademark) were applied on the nickel layer prepared in the above-describedstep “(2) Fabrication of Mask”, and the resulting product was heated at180 degrees for 20 minutes.

[0080] In this case, a device used for drawing a pattern for thetwo-dimensional photonic crystals 12 a, 12 b is JBX-5D II (manufacturedby JEOL). The pattern exhibits a structure, as shown in FIG. 2(b),wherein the two-dimensional photonic crystal plate 14 a (14 b) isconnected to an outer hull region 30 of the substrate by means of narrowbridges 32, whereby the photonic crystal plate 14 a (14 b) is supportedby these bridges 32. In this arrangement, through holes 18 for insertingmicrospheres 20 are defined at sites on a frame 16 a (16 b). In thepresent example, each circular hole having 1 μm diameter is defined.

[0081] Until now, where there appears a photonic bandgap is only indiamond and quasidiamond structures. A pattern shown in the presentexample, i.e., a pattern of the two-dimensional photonic crystal 12 a orthe two-dimensional photonic crystal 12 b shown in FIGS. 1(a) and 1(b)as well as FIGS. 2(a), 2(b), and 2(c) is for constituting a quasidiamondstructure so-called “woodpile” structure. The woodpile structure is theone wherein blocks are aligned in a striped-form, and then, furtherblocks are aligned thereon in such that the upper blocks becomeperpendicular striped-form, respectively with respect to the underblocks, so that a first layer and a third layer are out of alignmentwith respect to a second layer and a fourth layer, respectively, with aninterval of each half period.

[0082] A pattern of the two-dimensional photonic crystal 12 a or thetwo-dimensional photonic crystal 12 b shown in FIGS. 1(a) and 1(b) isdesigned so as to consequently obtain a woodpile structure, whenlaminated the two-dimensional photonic crystal plate 14 a and thetwo-dimensional photonic crystal plate 14 b while positioning them to befixed at accurate positions by the use of the through holes 18 being theones for positioning components therein and the microspheres 20 beingthe ones for positioning the components therewith. In the case where amaterial InP is used and designed so as to open a photonic bandgap in 4μm range, a relationship between widths and periods where the photonicbandgap opens is as indicated in FIG. 3, when a thickness of a plate issecured to 0.5 μm. A size of the two-dimensional photonic crystal plate14 a or the two-dimensional photonic crystal plate 14 b may be arrangedin such that a side L thereof is increased up to around 60 μm.

[0083] After drawing a pattern, the pattern was developed in thefollowing condition. Namely, a developing solution and a cleaningsolution are as follows.

[0084] Developing Solution: Orthoxylene (o-xylene; an organic compoundwherein methyl groups (CH₃—) are combined at adjacent corners of benzenering): isopropyl alcohol; (CH3)₂CHOH)=8:1

[0085] Cleaning Solution: Isopropyl alcohol

[0086] The two-dimensional photonic crystal plate 14 a (14 b) thus drawnis maintained in the developing solution for a period of from 20 secondsto 3 minutes, and then, it is further maintained in the cleaningsolution for a period of from 20 seconds to 3 minutes. Thereafter, thecleaning solution is dried off with an air gun from the resultingtwo-dimensional photonic crystal plate 14 a (14 b).

[0087] (4) Dry Etching

[0088] (4-1) Transfer of the Pattern from a Resist to a Metal Mask

[0089] For dry etching of the metal mask, an electron cyclotronresonance (ECR) ion shower device was used. A condition for etching a Nilayer is as follows.

[0090] Gas: Argon

[0091] Pressure: 0.5×10⁻⁴ Torr to 1.5×10⁻⁴ Torr

[0092] Acceleration Voltage: 0.5 kV to 1.0 kV

[0093] Microwave Output: 50 W to 100 W

[0094] Ion Current Density: 0.4 mA/cm² to 0.8 mA/cm²

[0095] Etching Time: 5 minutes to 10 minutes

[0096] Temperature: Room temperature

[0097] Subsequently, titanium is etched wherein a condition therefor isas follows.

[0098] Gas: Carbon tetrafluoride (CF₄)

[0099] Pressure: 0.5×10⁻⁴ Torr to 1.5×10⁻⁴ Torr

[0100] Acceleration Voltage: 0.5 kV to 1.0 kV

[0101] Microwave Output: 50 W to 100 W

[0102] Ion Current Density: 0.4 mA/cm² to 0.8 mA/cm²

[0103] Etching Time: 5 minutes to 10 minutes

[0104] Temperature: Room temperature

[0105] In order to completely remove a resist remained at the last, theresist is burned off in the following condition.

[0106] Gas: Oxygen

[0107] Pressure: 0.5×10⁻⁴ Torr to 1.5×10⁻⁴ Torr

[0108] Acceleration Voltage: 0.5 kV to 1.0 kV

[0109] Microwave Output: 50 W to 100 W

[0110] Ion Current Density: 0.4 mA/cm² to 0.8 mA/cm²

[0111] Etching Time: 5 minutes to 10 minutes

[0112] Temperature: Room temperature

[0113] (4-2) Transfer of the Pattern from the Metal Mask to an InP Layer

[0114] Inductively Coupled Plasma (ICP) was used for etching the InP.Etching was made under chlorine (Cl₂) atmosphere for a period of from 30seconds to 3 minutes.

[0115] (5) Wet Etching

[0116] (5-1) Release of the Metal Mask

[0117] For the sake of releasing the metal mask left in the dry etchingtreatment as described in the paragraph (4), the resultingtwo-dimensional photonic crystal plate 14 a (14 b) is shaken in bufferedhydrofluoric acid (20.8%) for about 10 minutes, and washed finally withpure water. Although a nickel layer is not dissolved into the bufferedhydrofluoric acid, a titanium layer laid under the nickel layer isdissolved, so that the metal mask can be removed completely.

[0118] (5-2) Partial Dissolution of InGaAs

[0119] For the sake of obtaining such a state wherein thetwo-dimensional photonic crystal plate 14 a (14 b) made of InP issupported merely on an outer hull region 30 with bridges 32 (see FIG.2(c)) as a result of solving out and removing an InGaAs layer laid underthe two-dimensional photonic crystal plate 14 a (14 b) of InP, thetwo-dimensional photonic crystal plate 14 a (14 b) is shaken in anetching solution (sulfuric acid:hydrogen peroxide water=1:1:3) for aperiod of 10 seconds to 60 seconds, and then, the resultingtwo-dimensional photonic crystal plate 14 a (14 b) is washed with purewater.

[0120] In FIG. 4, electron micrographs of the two-dimensional photoniccrystal plate 14 a (14 b) obtained by a manner as described above areshown.

[0121] It is to be noted herein that such two-dimensional photoniccrystal plate 14 a (14 b) connected to the outer hull region 30 withonly narrow bridges 30 in a state wherein it is held by the bridges 32just like it floats in midair is referred to as “air bridge typetwo-dimensional photonic crystal plate”.

[0122] (6) Lamination

[0123] The air bridge type two-dimensional photonic crystal plate 14 a(14 b) formed as described above is secured to a micromanipulationdevice.

[0124] In this case, the micromanipulation device means the one formanipulating a material of a submicron to micron order. Themicromanipulation device is provided with a sample table, and probeswherein the air bridge type two-dimensional photonic crystal plate 14 a(14 b) can be separated or picked up from the outer hull region 30 bymanipulating freely a probe or the like.

[0125] The micromanipulation device has been disposed in a samplechamber of a scanning electron microscope, and the two-dimensionalphotonic crystal plates 14 a (14 b) were laminated under observation ofthe electron microscope while manipulating a joy stick electricallyconnected to a movable shaft of the micromanipulation device. Since thepresent micromanipulation device may be provided with three probes at atime, when probes having different thicknesses from one another aremounted to the micromanipulation device according to application, avariety of manipulations can be continuously carried out withoutbreaking vacuum each time.

[0126] In the following, procedure steps for preparing athree-dimensional photonic crystal 30 by laminating two-dimensionalphotonic crystal plates 14 a (14 b) will be described by referring toFIGS. 5(a), 5(b) through FIGS. 7(a), 7(b).

[0127] (1) Procedure Step 1

[0128] Microspheres 20 have been strewed around an air bridge typetwo-dimensional photonic crystal plate 14 a (14 b). In this case, such asituation that the microspheres 20 are positioned on the air bridge typetwo-dimensional photonic crystal plate 14 a (14 b) must be avoided.

[0129] Then, the extreme end of a probe 40 is allowed to attach amicrosphere 20, and the probe 40 to which has been attached themicrosphere 20 is moved to fit the same into a through hole 18 definedon a frame 16 a (16 b) (see FIG. 5(a)).

[0130] In this case, it is to be noted that a radius of the through hole18 defined on the two-dimensional photonic crystal plate 14 a (14 b) isthe same as a thickness of the two-dimensional photonic crystal plate 14a (14 b). In other words, when the two-dimensional photonic crystalplate 14 a is superposed on the two-dimensional photonic crystal plate14 b, a diameter and a height of a circular cylinder defined by thethrough holes 18, 18, which have been defined at the same positions intwo pieces of the two-dimensional photonic crystal plates 14 a (14 b),are identical with each other. In this respect, a diameter of themicrosphere 20 coincides with the diameter as well as with the height ofthe above-described circular cylinder. A material of the microsphere 20may be, for example, a plastic such as polystyrene, an inorganiccompound such as silica, or the same material as that of thetwo-dimensional photonic crystal plate 14 a (14 b).

[0131] In order to manipulate such microsphere 20, a probe 40 havingaround 0.5 μm diameter in its extreme end thereof is used. When a top ofthe microsphere 20 is touched with the probe 40, the microsphere 20 issticked onto the extreme end of the probe 40 by means of electrostaticforce and/or van der Waals force. Either the microsphere 20 thus stickedonto the extreme end of the probe 40 is fitted into the through hole 18of the air bridge type two-dimensional photonic crystal plate 14 a (14b), which comes to be a first layer (see FIG. 5(b)), or the microsphere20 thus sticked is fitted into a hole of a two-dimensional photoniccrystal pattern (corresponding to the through hole 18), which has beendefined on an InP substrate by removing the air bridge typetwo-dimensional photonic crystal plate 14 a (14 b) in the case where thephotonic crystal pattern had been etched until it reaches the InPsubstrate (see FIG. 6(a)).

[0132] (2) Procedure Step 2

[0133] Then, the probe 40 is pushed against another air bridge typetwo-dimensional photonic crystal plate 14 a (14 b), which comes to be asecond layer, whereby the air bridge type two-dimensional photoniccrystal plate 14 a (14 b) is separated from bridges 32, and thetwo-dimensional crystal plate 14 a (14 b) thus separated is picked up bythe probe 40 to be placed on the first layer into which microspheres 20have been already inserted (see FIGS. 6(a) and 6(b), or FIGS. 7(a) and7(b). In this manipulation, a probe 40 having around 10 μm diameter inits extreme end is used.

[0134] In case of separating the air bridge type two-dimensionalphotonic crystal plate 14 a (14 b) from the bridges 32, when a sharpnotch has been previously given to each bridge 32 at a position, whereit is intended to be broken, it is effective for easily breaking thebridge 32 at the position corresponding to the notch.

[0135] A notch has been given to a junction between a two-dimensionalphotonic crystal plate 14 a (14 b) and each of the bridges 32, thetwo-dimensional photonic crystal plate 14 a (14 b) is easily separatedfrom the bridges 32, when notched positions in junctions are pushed bymeans of the probe 40. When the two-dimensional photonic crystal plate14 a (14 b) thus separated is touched with the extreme end of the probe40, it is sticked onto the extreme end of the probe 40 as in the casewhere a microsphere 20 is picked up by the probe 40.

[0136] (3) Procedure Step 3

[0137] In the case where a two-dimensional photonic crystal plate 14 a(14 b) is laminated on another two-dimensional photonic crystal plate 14b (14 a) wherein microspheres 20 have been already inserted into itsthrough holes 18, respectively, each hemispherical protruded portion ofa microsphere 20 functions as a guide for positioning thesetwo-dimensional photonic crystal plates 14 a (14 b) and 14 b (14 a).Accordingly, when the two-dimensional photonic crystal plate 14 a (14 b)is made to be close to a vicinity of correct laminating position,microspheres 20 engage with through holes 18 in the two-dimensionalphotonic crystal plate 14 a (14 b), respectively, so that thetwo-dimensional photonic crystal plate 14 a (14 b) is inevitably securedto the correct position. Furthermore, when the laminated two-dimensionalphotonic crystal plate 14 a (14 b) is pushed against the other plate 14b (14 a) laid below, both the two-dimensional photonic crystal plates 14a (14 b) and 14 b (14 a) become closely contact with each other.

[0138] (4) Procedure Step 4

[0139] Operations in the Procedure Steps 1 through 3 as described aboveare repeated.

[0140] FIGS. 8(a) and 8(b) are electron micrographs wherein FIG. 8(a) isthe one showing a state in which microspheres inserted into holes of the2D photonic plate, which has been defined on an InP substrate and FIG.8(b) is an enlarged one showing a part enclosed by a white rectangle inFIG. 8(a).

[0141] Likewise, FIGS. 9(a) and 9(b) are electron micrographs whereinFIG. 9(a) is the one showing a state in which two layers oftwo-dimensional photonic crystal plates 14 a (14 b) are laminated, andFIG. 9(b) is an enlarged one of a part enclosed by a white rectangle inFIG. 9(a).

[0142] As are the cases with the above figures, FIGS. 10(a) and 10(b)are electron micrographs wherein FIG. 10(a) is the one showing a statein which three layers of two-dimensional photonic crystal plates 14 a(14 b) are laminated, and FIG. 10(b) is an enlarged one of apartenclosed by a white rectangle in FIG. 10(a).

[0143] Moreover, FIG. 11 is an electron micrograph showing a statewherein bridges 32 are pushed by a probe 40 to cut off a two-dimensionalphotonic crystal plate 14 a (14 b) from an outer hull region 30 of asubstrate.

[0144]FIG. 12 is an electron micrograph showing a state wherein atwo-dimensional photonic crystal 14 b (14 a), which has been cut off andsticked onto a probe, is brought on another two-dimensional photoniccrystal 14 a (14 b) in which microspheres 20 used for positioning havebeen inserted into through holes 18.

[0145]FIG. 13 is an electron micrograph showing a state wherein twopieces of two-dimensional photonic crystal plates 14 a (14 b) aresuperposed substantially completely one another.

[0146] In the following, optical characteristics will be described withrespect to the above-described examples. A measuring condition for theoptical characteristics is as follows.

[0147] Measuring Device: Measuring device for spectra of reflected waves

[0148] Resolution: 16 μm⁻¹

[0149] Angle of Incidence: 20 degrees (spread angle ±10 degrees) A statewherein cone-like light is input to a sample centering around 20 degrees

[0150] Polarized Light: None

[0151] Detector: MCT, 77K cooling

[0152] Number of Times in Scanning: 1024

[0153] Scanned Wavelength Zone: 1.43 μm to 14.3 μm

[0154] Detected light: Reflected light

[0155] Since the three-dimensional photonic crystal described in theexamples is designed so as to open a photonic bandgap in 4 μm zone, thelight in 4 μm zone should be perfectly reflected by thethree-dimensional photonic crystal in the case when reflected waves weremeasured.

[0156]FIG. 14 is a graphical representation indicating spectra in thecase when reflected waves are measured in the above-described conditionwith each increase of one layer of a two-dimensional photonic crystalplate wherein one layer (¼ period), three layers (¾ period), and fourlayers (one period) are laminated one another. With increase in thenumber of layer, each peak of wavelength in 4 μm band became stronger.This means that a photonic bandgap is formed gradually. Furthermore,each sharp gap appearing in a central portion of each peak is derivedfrom absorption due to stretch of carbonyl (C═O) of carbon dioxide inair. Each peak appearing in 2 μm band exhibits reflection due to ahigher mode.

[0157] A wavelength threshold of photonic bandgap may be set, forexample, to 100 nm to 1 mm.

[0158] As described above, a phase in a direction perpendicular to asurface of a two-dimensional photonic crystal plate 14 a (14 b) isallowed to change arbitrarily, so that the two-dimensional photoniccrystal plate 14 a (14 b) can be laminated as designed. Accordingly,this is a manner suitable for preparing photonic band crystals.

[0159] In addition, since a lithographic technique is used in theabove-described embodiment, it becomes possible to introduce anarbitrary optical phase control region (defect region).

[0160] More specifically, when a three-dimensional photonic crystal 10is prepared by laminating two-dimensional photonic crystal plates 14 a(14 b) as described above, not only a simple lamination of thetwo-dimensional photonic crystal plates 14 a (14 b) is conducted by theuse of a probe 40, but also minute components such as light-emittingmaterials, and defect components, which constitute an optical phasecontrol region (defect region), can be inserted into (embedded in) thetwo-dimensional photonic crystal plates 14 a (14 b) in case of preparingthe three-dimensional photonic crystal with the use of the probe 40.

[0161] In this case, it is not necessary that quality of material inthese minute components is the same as that of the two-dimensionalphotonic crystal plates 14 a (14 b), but the above-describedlight-emitting materials each having different quality of material ormaterials each having a different refractive index from that of theabove-described two-dimensional photonic crystal plate 14 a (14 b) maybe used.

[0162] Furthermore, since a lithographic technique is used in theabove-described embodiment, a three-dimensional minute structure ofaround submicron order can be arranged, so that the resulting productcan be applied to an optical element used in a wavelength region having0.2 μm to 10 μm wavelengths of light.

[0163] It is to be noted that the above-described embodiment as well asexamples may be modified as in the following paragraphs (1) through (8).

[0164] (1) In the above-described embodiment, a probe prepared bymetal-coating around glass fibers is used as a probe 40 wherein adiameter of the extreme end of the probe (corresponding to a part of theglass fibers) has been made to be around 0.5 μm. However, the presentinvention is not limited thereto as a matter of course. For instance, aprobe may be made optionally from glass, metals and the like. Anadhesive force for sticking a two-dimensional photonic crystal plate 14a (14 b) or a microsphere 20 onto the extreme end of a probe may bearranged to control by means of ON/OFF of electric field. Besides, forthe sake of increasing sticking performance by expanding a contact areawith respect to a two-dimensional photonic crystal plate 14 a (14 b), adiameter of the extreme end of a probe may be increased to a value morethan that of micron order, for example, it may be a value extending from10 nm to 1 mm.

[0165] More specifically, a probe, for example, as shown in FIGS. 15(a),15(b), and 15(c) may be used. A probe 400 shown in FIGS. 15(a), 15(b),and 15(c) is composed of an inner core 402, an insulating layer 404formed around the inner core 402, and an outer metallic film 406 formedon an outer periphery of the insulating layer 404 except for an extremeend portion T thereof.

[0166] In this case, the inner core 402 is made from a hard metal suchas tungsten, while the insulating layer 404 is formed by depositingSiO₂, SiN_(x) or the like in accordance with CVD and the like.Furthermore, the outer metallic film 406 is formed by depositing Ni orAu in accordance with a manner such as vapor deposition.

[0167] The extreme end portion T formed by the insulating layer 404 isconstituted so as to define a flat surface and a size of which is, forexample, “1 μm×1 μm=1 μm²” to “10 mm×10 mm=100 mm²” in the case wherethe extreme end portion T is square.

[0168] In the probe 400, when a voltage is applied across the inner core402 and the outer metallic film 406, an electric field appears in thevicinity of an edge of the extreme end portion T, whereby atwo-dimensional photonic crystal plate 14 a (14 b) or a microsphere 20can be electrostatically adhered.

[0169] In this case, the outer metallic film 406 functions as a shieldby which electric field is not leaked to the outside. If there is noshield, a picture image is confused in case of observation by electronmicroscope. For this reason, it is preferred to provide a shield.

[0170] In addition, the outer metallic film 406 functions also tostabilize electric potential in a two-dimensional photonic crystal plate14 a (14 b). In general, a minute substance under observation ofelectron microscope has been charged at a variety of electric potentialsdependent upon an observing condition at that time, or a history untilthat moment. Accordingly, a certain minute substance is not necessarilysticked by a probe to which a voltage has been previously applied.

[0171] However, when it is arranged in such that the outer metallic film406 has been in contact with a two-dimensional photonic crystal plate 14a (14 b), an electric potential of the two-dimensional photonic crystalplate 14 a (14 b) is fixed to an equipotential state in the outermetallic film 406. Accordingly, adhesion or separation can be madealways in accordance with manipulator's intension with goodreproducibility.

[0172] FIGS. 16(a), and 16(b) are diagrams each showing a structure ofanother probe wherein a probe 410 is modified in such that an extremeend electrode section of a probe as shown in FIGS. 15(a), 15(b), and15(c) is made to be comb-shaped, whereby its adhesive force is elevated.

[0173] Namely, an insulator needle 412 an extreme end portion of whichis made to be a flat surface is provided with a first electrode 414 anda second electrode 416 in the probe 410. In this case, the firstelectrode 414 and the second electrode 416 are arranged to constitutecomb-shaped electrodes (convex and concave portions of the first and thesecond electrodes 414 and 416 correspond to teeth of combs,respectively, and they are staggered with each other) on the flatsurface of the extreme end portion of the insulator needle 412.

[0174] After forming the first electrode 414 and the second electrode416 in accordance with the manner as described above, an insulating film418 made of SiO₂ or the like is deposited thereon to cover these firstand second electrodes 414 and 416. A metallic shield 420 is formed onthe outer periphery of the insulating film 418 except for a side of theextreme end portion, which has been made to be a flat surface, of theinsulator needle 412.

[0175] In the above-described probe 410, when different voltages withrespect to the metallic shield 420 (ground) are applied to the firstelectrode 414 and the second electrode 416, respectively, an electricfield appears on the flat surface in the extreme end portion of theinsulator needle 412, whereby a two-dimensional photonic crystal plate14 a (14 b) or a microsphere 20 can be electrostatically adhered.

[0176] (2) In the above-described embodiment, positioning forsuperposing two-dimensional photonic crystal plates 14 a and 14 b hasbeen conducted by inserting microspheres 20 into through holes 18defined on frames 16 a and 16 b of the two-dimensional photonic crystalplates 14 a and 14 b. However, the invention is not limited thereto as amatter of course. For instance, two-dimensional photonic crystal plates14 a and 14 b may be allowed to abut against a structure having apredetermined configuration such as a wall surface to position them oneanother. In this case, it is preferred that respective sections of thetwo-dimensional photonic crystal plate 14 a and the two-dimensionalphotonic crystal plate 14 b have the same dimensions, respectively, witheach other.

[0177] More specifically, a wall surface 500 involving at least onecorner and constituted with concavo-convex planes may be provided asshown in FIG. 18(a), and outside surfaces of frames 16 a and 16 b oftwo-dimensional photonic crystal plates 14 a and 14 b are allowed toabut against the wall surface 500 to implement positioning of thetwo-dimensional photonic crystal plates 14 a and 14 b. In this casealso, it is preferred that respective sections of the two-dimensionalphotonic crystal plate 14 a and the two-dimensional photonic crystalplate 14 b have the same dimensions, respectively, with each other.

[0178] Likewise, a flat wall surface 502 involving at least one cornermay be constituted as shown in FIG. 18(b), and outside surfaces offrames 16 a and 16 b of two-dimensional photonic crystal plates 14 a and14 b are allowed to abut against the wall surface 502 to conductpositioning of the two-dimensional photonic crystal plates 14 a and 14b. In this case also, it is preferred that respective sections of thetwo-dimensional photonic crystal plate 14 a and the two-dimensionalphotonic crystal plate 14 b have the same dimensions, respectively, witheach other.

[0179] Furthermore, a plurality of columns 504 may be set up as shown inFIG. 18(c), and outside surfaces of frames 16 a and 16 b oftwo-dimensional photonic crystal plates 14 a and 14 b are allowed toabut against these columns 504 to effect positioning of thetwo-dimensional photonic crystal plates 14 a and 14 b. In this casealso, it is preferred that respective sections of the two-dimensionalphotonic crystal plate 14 a and the two-dimensional photonic crystalplate 14 b have the same dimensions, respectively, with each other.

[0180] Moreover, it may be arranged in such that a concave 506 isdefined as shown in FIG. 18(d), and outside surfaces of frames 16 a and16 b of two-dimensional photonic crystal plates 14 a and 14 b areallowed to abut against a wall surface 506 a defined by the concave 506to effect positioning of the two-dimensional photonic crystal plates 14a and 14 b. In this case also, it is preferred that respective sectionsof the two-dimensional photonic crystal plate 14 a and thetwo-dimensional photonic crystal plate 14 b have the same dimensions,respectively, with each other.

[0181] Besides, a plurality of rectangular solids 508 may be set up asshown in FIG. 19(a), and outside surfaces of frames 16 a and 16 b oftwo-dimensional photonic crystal plates 14 a and 14 b are allowed toabut against these rectangular solids 508 to conduct positioning of thetwo-dimensional photonic crystal plates 14 a and 14 b. In this casealso, it is preferred that respective sections of the two-dimensionalphotonic crystal plate 14 a and the two-dimensional photonic crystalplate 14 b have the same dimensions, respectively, with each other.

[0182] In addition, a plurality of L-shaped members 510 may be set up asshown in FIG. 19(b), and outside surfaces of frames 16 a and 16 b oftwo-dimensional photonic crystal plates 14 a and 14 b are allowed toabut against these L-shaped members 510 to make positioning of thetwo-dimensional photonic crystal plates 14 a and 14 b. In this casealso, it is preferred that respective sections of the two-dimensionalphotonic crystal plate 14 a and the two-dimensional photonic crystalplate 14 b have the same dimensions, respectively, with each other.

[0183] According to the manners as described above, there is no need todefine through holes 18 and the like on frames 16 a and 16 b oftwo-dimensional photonic crystal plates 14 a and 14 b, besides, it isnot required to use any microsphere 20, so that the two-dimensionalphotonic crystal plates 14 a and 14 b can be easily positioned.

[0184] (3) The following materials can be used as the one for atwo-dimensional photonic crystal plate.

[0185] The group III-V, the group VI, and the group II-VI semiconductorssuch as InP, GaAs, and InGaAs-based semiconductors

[0186] Si, Ge, and SiGe-based semiconductors

[0187] AlInGaN-based semiconductors

[0188] ZnMgCdTeSe-based semiconductors and the like

[0189] Insulators of SiN_(x), SiO₂, TiO₂ and the like

[0190] Organic matters of PMMA, polyimide and the like

[0191] (4) In the above-described embodiment, although a profile of athrough hole 18 defined on frames 16 a and 16 b of two-dimensionalphotonic crystal plates 14 a and 14 b has been a circle, and a contourof a microsphere has been constituted in a spherical body, the inventionis not limited thereto as a matter of course. Accordingly, a profile ofthe through hole 18 to be defined on frames 16 a and 16 b oftwo-dimensional photonic crystal plates 14 a and 14 b may be anarbitrary profile such as square, and rectangle, while a contour of amicrosphere 20 may be an arbitrary one such as regular hexahedron, andrectangular solid so as to fit in the profile of the through hole 18.

[0192] (5) In the above-described embodiment, explanation has been suchthat two types of two-dimensional photonic crystal plates such as atwo-dimensional photonic crystal plate 14 a and a two-dimensionalphotonic crystal plate 14 b are employed, and these plates are laminatedalternately so as to obtain a periodical structure in response towavelengths of light to form a three-dimensional photonic crystal 10.However, the invention is not limited thereto as a matter of course.Namely, three types or more of two-dimensional photonic crystal platesmay be laminated so as to obtain a periodic structure in response towavelengths of light, whereby a three-dimensional photonic crystal isconstituted.

[0193] (6) While an explanation has been omitted in the above-describedembodiment, plural types of two-dimensional photonic crystal platesnecessary for constituting a three-dimensional photonic crystal may befabricated either on a single substrate in a lump as in the case of thetwo-dimensional photonic crystal plate 14 a and the two-dimensionalphotonic crystal plate 14 b in the above-described embodiment, or ondifferent substrates, respectively.

[0194] (7) In the above-described embodiment, through holes 18 have beendefined on frames 16 a and 16 b, but the invention is not limitedthereto as a matter of course.

[0195] For instance, as shown in FIG. 17(a), two-dimensional photoniccrystal plates adjacent to each other among a plurality oftwo-dimensional photonic crystal plates are correctly laminated witheach other, and in this case, positions in the two-dimensional photoniccrystal plates thus laminated at which patterns passing through each ofthe laminated two-dimensional photonic crystal plates amongtwo-dimensional photonic crystal patterns of the laminatedtwo-dimensional photonic crystal plates correspond to each other may beused as through holes.

[0196] On one hand, through holes are defined in a region surrounded bytwo-dimensional photonic crystal patterns of two-dimensional photoniccrystal plates as shown in FIG. 17(b), and a positioning member may belocated in the thorough holes thus defined.

[0197] (8) The above-described embodiment as well as the modificationsdescribed in the paragraphs (1) through (7) may be optionally combinedwith each other.

[0198] Since the present invention has been constituted as describedabove, an advantage of providing a practically effectivethree-dimensional photonic crystal, and a process for the productionthereof as well as a probe used therefor can be obtained.

[0199] More specifically, it becomes possible to realize an opticaldevice wherein three-dimensional photonic crystals are employed by thepresent invention. Optical devices wherein three-dimensional photoniccrystals are used include, for example, low threshold laser device,light-emitting device, lossless circuit, branching filter and the like.When an active element such as laser device, and light-emitting deviceis fabricated from three-dimensional photonic crystals, advantages ofreduction in driving electric power, first wavelength oscillation andthe like are obtained.

[0200] On one hand, when a passive element such as lossless circuit, andbranching filter is fabricated from three-dimensional photonic crystals,such device is very small as compared with a conventional optical fiberand the like, so that a highly integrated optical circuit can beobtained.

[0201] In other words, the above-described process for the production ofthree-dimensional photonic crystals according to the present inventionis excellent particularly in the following points.

[0202] (1) Since a manner for laminating two-dimensional photoniccrystal plates is employed, structural accurancy is maintained. Nomatter how thick the crystal becomes. Accordingly, a highly accuratethree-dimensional photonic crystal in response to optical wavelengthscan be fabricated.

[0203] (2) Since a manner for laminating two-dimensional photoniccrystal plates is employed, an arbitrary structural body can befabricated by lamination. Accordingly, fabrication of diamond andquasidiamond periodic crystals is possible, so that fabrication ofphotonic bandgap crystals becomes possible.

[0204] (3) Since a manner for laminating two-dimensional photoniccrystal plates is employed, an optical phase control region (defectregion) can be easily inserted into a three-dimensional photoniccrystal.

[0205] Therefore, a process for the production of three-dimensionalphotonic crystals according to the present invention is suitable forfabricating optical devices.

[0206] It will be appreciated by those of ordinary skill in the art thatthe present invention can be embodied in other specific forms withoutdeparting from the spirit or essential characteristics thereof.

[0207] The presently disclosed embodiments are therefore considered inall respects to be illustrative and not restrictive. The scope of theinvention is indicated by the appended claims rather than the foregoingdescription, and all changes that come within the meaning and range ofequivalents thereof are intended to be embraced therein.

[0208] The entire disclosure of Japanese Patent Application No.2001-228287 filed on Jul. 27, 2001 including specification, claims,drawing and summary are incorporated herein by reference in itsentirety.

What is claimed is:
 1. A three-dimensional photonic crystal, comprising:a plurality of two-dimensional photonic crystal plates each providedwith different types of two-dimensional photonic crystals; and saidpluralities of two-dimensional photonic crystal plates being positionedrespectively to be laminated so as to obtain a periodic structure inresponse to wavelengths of light.
 2. A three-dimensional photoniccrystal, comprising: a plurality of two-dimensional photonic crystalplates each provided with through holes and different types oftwo-dimensional photonic crystals; a plurality of positioning members tobe located in said through holes in said plurality of thetwo-dimensional photonic crystal plates; and said positioning membersbeing located in said through holes in the two-dimensional photoniccrystal plates adjacent to each other among said pluralities oftwo-dimensional photonic crystal plates to be laminated in such thatsaid pluralities of the two-dimensional photonic crystal plates obtain aperiodic structure in response to wavelengths of light.
 3. Athree-dimensional photonic crystal, comprising: a flat plate-like firsttwo-dimensional photonic crystal plate provided with first through holeson a first frame as well as with first two-dimensional photonic crystalsin a region inside said first frame; a flat plate-like secondtwo-dimensional photonic crystal plate provided with second throughholes, being positioned with respect to said first through holes, on asecond frame as well as with second two-dimensional photonic crystals ina region inside said second frame; positioning members located in suchthat said first through holes being communicated with said secondthrough holes; and said positioning members being located in such thatsaid through holes in said first two-dimensional photonic crystal platebeing communicated with said through holes in said secondtwo-dimensional photonic crystal plate to be positioned, whereby saidfirst two-dimensional photonic crystal plate is laminated with saidsecond two-dimensional photonic crystal plate so as to obtain a periodicstructure in response to wavelengths of light.
 4. A three-dimensionalphotonic crystal as claimed in claim 3 wherein said first through holesand said second through holes are circular holes, respectively, a radiusin each of said circular holes is substantially equal to thicknesses ofsaid first two-dimensional photonic crystal plate and said secondtwo-dimensional photonic crystal plate, and each of said positioningmembers is a sphere having a diameter corresponding to substantiallydoubled radius of said circular hole.
 5. A process for the production ofa three-dimensional photonic crystal, comprising the steps of: allowingpluralities of two-dimensional photonic crystal plates each providedwith different types of two-dimensional photonic crystals to adhere orto be held onto the extreme end of a probe in accordance withmicromanipulation thereby moving them, respectively; and positioningsaid pluralities of two-dimensional photonic crystal plates with eachother by means of moving them wherein these two-dimensional photoniccrystal plates have been allowed to adhere or to be held onto theextreme end of said probe, so that said pluralities of two-dimensionalphotonic crystal plates are laminated so as to obtain a periodicstructure in response to wavelengths of light.
 6. A process for theproduction of a three-dimensional photonic crystal as claimed in claim 3wherein said two-dimensional photonic crystal plates are allowed toadhere or to be held onto the extreme end of said probe by means ofelectrostatic adhesion wherein a predetermined voltage is applied tosaid probe.
 7. A process for the production of a three-dimensionalphotonic crystal as claimed in any one of claims 5 and 6 wherein saidtwo-dimensional photonic crystal plates are connected to outer hullregions with bridges held in midair; and applying a load to said bridgeswith said probe to break down them thereby allowing said two-dimensionalphotonic crystal plates to adhere on the extreme end of said probe tomove them as a result of such break-down of the bridges.
 8. A processfor the production of a three-dimensional photonic crystal as claimed inany one of claims 5 and 6 wherein said respective positioning of thepluralities of two-dimensional photonic crystal plates is conducted bymoving each of said pluralities of two-dimensional photonic crystalplates with said probe, and each of said pluralities of two-dimensionalphotonic crystal plates is allowed to abut against a structural bodyhaving a predetermined shape.
 9. A process for the production of athree-dimensional photonic crystal as claimed in claim 7 wherein saidrespective positioning of the pluralities of two-dimensional photoniccrystal plates is conducted by moving each of said pluralities oftwo-dimensional photonic crystal plates with said probe, and each ofsaid pluralities of two-dimensional photonic crystal plates is allowedto abut against a structural body having a predetermined shape.
 10. Aprocess for the production of a three-dimensional photonic crystal asclaimed in any one of claims 5 and 6 wherein each of said pluralities oftwo-dimensional photonic crystal plates is a flat plate-like bodywherein through holes have been defined on its frame part, besides aregion inside said frame part is provided with different types oftwo-dimensional photonic crystals from one another; and positioningmembers are located in said through holes in two-dimensional photoniccrystal plates adjacent to each other among said pluralities oftwo-dimensional crystal plates to position them, whereby saidpluralities of two-dimensional photonic crystal plates are laminated soas to obtain a periodic structure in response to wavelengths of light.11. A process for the production of a three-dimensional photonic crystalas claimed in claim 7 wherein each of said pluralities oftwo-dimensional photonic crystal plates is a flat plate-like bodywherein through holes have been defined on its frame part, besides aregion inside said frame part is provided with different types oftwo-dimensional photonic crystals from one another; and positioningmembers are located in said through holes in two-dimensional photoniccrystal plates adjacent to each other among said pluralities oftwo-dimensional crystal plates to position them, whereby saidpluralities of two-dimensional photonic crystal plates are laminated soas to obtain a periodic structure in response to wavelengths of light.12. A process for the production of a three-dimensional photonic crystalas claimed in claim 10 wherein each of said through holes is a circularhole; a radius of said circular hole is substantially equal to eachthickness of said pluralities of two-dimensional photonic crystalplates; and each of said positioning members is a sphere a diameter ofwhich is equal to a substantially doubled radius of said circular hole.13. A process for the production of a three-dimensional photonic crystalas claimed in claim 11 wherein each of said through holes is a circularhole; a radius of said circular hole is substantially equal to eachthickness of said pluralities of two-dimensional photonic crystalplates; and each of said positioning members is a sphere a diameter ofwhich is equal to a substantially doubled radius of said circular hole.14. A process for the production of a three-dimensional photonic crystalas claimed in any one of claims 5 and 6 wherein a micro- and/orsubmicro-part for constituting an optical phase controlling region isinserted by means of said probe in the case when said pluralities oftwo-dimensional photonic crystal plates are laminated so as to obtain aperiodic structure in response to wavelengths of light.
 15. A processfor the production of a three-dimensional photonic crystal as claimed inclaim 7 wherein a micro- and/or submicro-part for constituting anoptical phase controlling region is inserted by means of said probe inthe case when said pluralities of two-dimensional photonic crystalplates are laminated so as to obtain a periodic structure in response towavelengths of light.
 16. A process for the production of athree-dimensional photonic crystal as claimed in claim 8 wherein amicro- and/or submicro-part for constituting an optical phasecontrolling region is inserted by means of said probe in the case whensaid pluralities of two-dimensional photonic crystal plates arelaminated so as to obtain a periodic structure in response towavelengths of light.
 17. A process for the production of athree-dimensional photonic crystal as claimed in claim 9 wherein amicro-and/or submicro-part for constituting an optical phase controllingregion is inserted by means of said probe in the case when saidpluralities of two-dimensional photonic crystal plates are laminated soas to obtain a periodic structure in response to wavelengths of light.18. A process for the production of a three-dimensional photonic crystalas claimed in claim 10 wherein a micro- and/or submicro-part forconstituting an optical phase controlling region is inserted by means ofsaid probe in the case when said pluralities of two-dimensional photoniccrystal plates are laminated so as to obtain a periodic structure inresponse to wavelengths of light.
 19. A process for the production of athree-dimensional photonic crystal as claimed in claim 11 wherein amicro- and/or submicro-part for constituting an optical phasecontrolling region is inserted by means of said probe in the case whensaid pluralities of two-dimensional photonic crystal plates arelaminated so as to obtain a periodic structure in response towavelengths of light.
 20. A process for the production of athree-dimensional photonic crystal as claimed in claim 12 wherein amicro- and/or submicro-part for constituting an optical phasecontrolling region is inserted by means of said probe in the case whensaid pluralities of two-dimensional photonic crystal plates arelaminated so as to obtain a periodic structure in response towavelengths of light.
 21. A process for the production of athree-dimensional photonic crystal as claimed in claim 13 wherein amicro- and/or submicro-part for constituting an optical phasecontrolling region is inserted by means of said probe in the case whensaid pluralities of two-dimensional photonic crystal plates arelaminated so as to obtain a periodic structure in response towavelengths of light.
 22. A probe, comprising: an inner core made of ametal; an insulating layer formed around said inner core; an outermetallic film formed on the outer periphery of said insulating layerexcept for the extreme end portion thereof; the extreme end portion ofsaid insulating layer having a shape of a flat surface; and an electricfield being generated in the vicinity of marginal portion of saidextreme end portion by applying a voltage across said inner core andsaid outer metallic film so that a material is electrostaticallyadhered.
 23. A probe, comprising: an insulator needle the extreme endportion of which is a flattened surface; a first electrode and a secondelectrode disposed on said insulator needle so as to constitute a combelectrode in said flattened surface of said extreme end portion in saidinsulator needle; an insulating film covering said insulator needleprovided with said first electrode and said second electrode; a metallicshield formed on the outer periphery of said insulating film except fora side of said extreme end portion, which is said flattened surface ofsaid insulator needle; and an electric field being generated over saidflattened surface in said extreme end portion of said insulator needleby applying different voltages with respect to said metallic shield fromone another to said first electrode and said second electrode,respectively, so that a material is electrostatically sticked.